Fermentation phytosterols

One possible explanation for why the oils were not enriched is that they were diluted out by yeast and gypsum, from neutralizing with lime, mixed in with the recovered SSF residue. This possibility was partially tested by extracting the oils from the washed, pretreated QF prior to fermentation. The washed solids analyzed prior to neutralization and SSF contained 7 times more oil and 4.8 times more total phytosterols (pre-SSF, Table 3) than the recovered solid post-SSF. Therefore, pretreated QF is a valuable source of phytosterols, provided that they are recovered from the solids prior to SSF. 

The residual solids from the QF pretreated for the FBR5 fermentation were analyzed for their oil content. The total oil content for the washed cake (Table 3) was 8.28% (w/dw) and the yield of total phytosterols was equal to 1.89% (w/dw). The yield compared favorably to that of an earlier study in which com fiber was pretreated with dilute H2S04 for which the yield of total phytosterols was 1.43% (w/dw) (22). The pretreatment step concentrated the total phytosterols 26 times compared to untreated QF (2). 

Luparia, V., Soubeyrand, V., Berges, T., Julien, A., and Salmon, J. M. (2004). Assimilation of grape phytosterols by Saccharomyces cerevisiae and their impact on enological fermentations. Appl. Microbiol. Biotechnol. 65, 25-32. 

The recovery of phytosterols or their concentration is the third step in their isolation. Methyl esters of fatty acids are distilled to raise the phytosterol content up to 50% by weight. Molecular distillation can be used for phytosterols. Phytosterol concentrates are used as raw materials for steroid drug preparation via microbial fermentation, in which the pure form of phytosterols are not necessary. The final recovery of phytosterols can be achieved by crystallization (physical), solvent extraction (chemical), or crystallization with additives via adduct formation and separation (physicochemical). Organic solvents or solvent mixtures composed of low- and high-polarity solvents and water are used for crystallization of phytosterols... 

Fermentation of a mixture of soy sterols, sitosterol, stigmasterol and traces of related compounds with Microbacteria sp. produces androstenedione (1-6). Relatively recent patents describe the production of the steroid from phytoserols from various crude vegetable oils, bypassing the need for prior isolation of the phytosterol fraction. 

EC Commission decision of 31 March 2004 authorizing the placing on the market of yellow fat spreads, salad dressings, milk type products, fermented milk type products, soya drinks and cheese-type products with added phytosterols/phytostanols as novel food ingredients under Regulation (EC) No 258/97 of the European Parliament and of the Council [notified under document number C(2004) 1243]. Official Journal 2004, L 105,14/04/2004, 0040-0042. 

Limonene as a by-product of orange juice production can be used for polymer production together with CO2 to form a polystyrol-like foam. Menthon can be used as a precursor for branched dicarbonic acids and alpha-pinen (a by-product of the forest industry) as precursor for cymol production or for enzymatic verbenone production. Other important terpenoids are phytosterols. They are used in the production of steroid hormones such as cortison or progesteron by Bayer Sobering Pharma. Probably the most important example where plant secondary metabolism and microbial fermentation are synergistically combined, steroid hormones, are produced from phytosterols. A fermentation process by Bayer Schering Pharma uses a plant metaboUte and converts it by a single-step microbial fermentation into the desired end product. 

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